The Australian Broadcasting Corporation cited an unnamed special forces commander as saying: "We have Australian Army and Australian Special Forces assisting the PNGDF (Papua New Guinea Defence Force), making sure the counter-terrorism provision of services is first class."

Elite Australian troops are already on the ground in the capital, ABC reported.

The broadcaster also said Australian warships would be used to protect cruise liners that have been hired to provide temporary accommodation for the November 12-19 summit due to a shortage of hotels.

An Australian Defence Force spokesperson confirmed Canberra was providing "advisory assistance", but that the final shape of that help would depend on what was requested.

Australian and New Zealand police are also in Papua New Guinea to train local officers in areas such as close personal protection and special event planning.

- 'Raskols' -

The Economist Intelligence Unit ranks Port Moresby 136th out of 140 on its list of the world's most livable cities.

Many businesses have armed guards and those that can afford to live in walled compounds protected by razor-wire. There is a constant threat of car jackings and robbery from gangs known as "raskols".

The US Coast Guard said last month that it would help with "inshore security" during the summit.

Papua New Guinea's APEC Minister Justin Tkatchenko said all 21 nations attending APEC would contribute to the security effort.

"Cooperation is even more important for Papua New Guinea, where we do not have the security assets and resources of other countries," he recently told parliament.

"We are working with our partners so that we can deploy fighter jets in our skies, enhance maritime security and deliver joint special forces operations."

Papuan forces have conducted mock counter-terrorism exercises in the capital, including hostage rescue, as well as practising crowd control and clearance techniques.

Tkatchenko said APEC was the biggest logistical challenge ever faced by the country, outlining problems such as finding parking space for visiting leaders' aircraft and the shortage of temporary accommodation.

While PNG does not have a domestic terrorism threat, Tkatchenko acknowledged "the threat of crime and terrorism is real in every country" when such a meeting is being held.

Prime Minister Peter O'Neill has described APEC as an opportunity for Papua New Guinea to shed its dismal image and showcase "a culturally rich, economically modernising country".